The dumbbell flye on a Swiss ball increases strength in the chest, shoulder and triceps. The unstable surface of the Swiss ball increases the difficulty of the movement and improves core stability.
Grab a pair of dumbbells with palms facing each other. Situate your upper and middle back on the Swiss ball. Bend knees 90-degrees while keeping hips high. Exhale and press both dumbbells to the ceiling and pause.
Inhale and slowly lower dumbbells to sides until arms are almost fully extended with slight bend to elbow and parallel with chest. Pause. Exhale and contract chest as you retract back to starting position.
Make sure you keep a slight bend in the elbows throughout the movement.